Traffic calming, while popular in Europe for decades, is still in its infancy stages in the US. More and more cities across America have begun installing these devices as a solution to speeding traffic on residential roads. In the past several years, the use of rubber traffic calming devices has escalated dramatically. But what is the difference between the various devices and their applications on local roads? While varying in popularity, speed humps, tables, cushions, bumps, and traffic circles all have their own unique usages and configurations.
Below, Traffic Logix, a leader in rubber traffic calming solutions, explains what makes each device unique, and where and why that specific solution should be used. While each of the solutions described below is unique, all of them are physical traffic calming measures which compel drivers to slow down and are effective in improving street safety.
Speed Humps: Often considered the most common traffic calming devices, speed humps are used to address issues of excessive vehicle speed and volume. Speed humps are circular in shape and used on residential roads to slow cars to between 10 and 20 miles per hour.
Speed humps are often installed in a series to avoid speeding before and after the hump. They are usually placed on residential streets and are not used on major thoroughfares, bus routes, or primary emergency response routes. Ideally, they are installed mid-block between intersections, approximately 200 feet from the intersection with 600 feet between devices.
Studies conducted by the Institute of Transportation Engineers found that speed humps, on average, reduced traffic volume by 18% and collisions by 13%.
Traffic Logix speed humps are either 3 or 4 inches high and come in lengths of 7 or 14 feet, although they are customizable in 18 inch increments.
Speed Tables: Similar to speed humps, although with long flat-topped centers, speed tables slow cars more gradually than speed humps do. Speed tables are used on residential roads to slow cars to estimated speeds of 20-35 mph.
The flat top of a speed table is generally long enough for the entire length of a car to rest on top. This design lets cars drive over the table without slowing down as much as for speed humps or cushions. Speed tables are therefore used on roads with typical residential speed limits.
A study conducted by Fehr and Peers of 8 speed table sites found a 45% decrease in accidents per year with the use of speed tables.
Traffic Logix speed tables are 3 inches high and come in standard lengths of 10.5, 14 or 21 feet although they are customizable to additional lengths.
Speed Cushions: The newest available traffic calming device, speed cushions (also called speed lumps) are used to slow cars down without affecting emergency vehicles. Speed cushions are used on residential roads to slow cars to approximately 15-25 mph.
Designed as several small speed humps, cushions force passenger vehicles to slow down with one or both wheels on the cushion. The split design, however, allows the wider axle of emergency vehicles to pass speed cushions without delaying their response times.
Since speed cushions are a newer device, there are no formal studies documenting their effect. Informal studies indicate that cushions slow cars similar to humps. One Florida community that used Traffic Logix speed cushions reported that the 85th percentile speed was reduced from 38 mph to 26 mph.
Traffic Logix speed cushions are 3 inches in height and 7 feet long.
Speed Bumps: Sometimes colloquially used to describe the whole gamut of traffic calming devices, speed bumps are in fact primarily used off the road- in parking lots or alleyways. Speed bumps slow traffic nearly to a halt.
Traffic Logix speed bumps are 2 ¼ inches high and 4 or 6 feet long.
Traffic Circles: Placed in the heart of intersections, traffic circles are raised islands that slow cars by forcing them to drive around a circle, thus impeding vehicle speed. The speed to which cars are slowed is dependent on various factors such as the circumference of the circle, and the configuration of the approaching streets.
Traffic Logix rubber curbing consists of units of flexible rubber that are bent and installed around a landscaped area.
Traffic Logix, which manufactures and sells a full range of rubber traffic calming devices, reports that speed cushions are the best-selling solution, probably because of their compatibility with emergency vehicles. Many cities are concerned about traffic calming devices affecting response time. “We work closely with each city we serve, ensuring that the devices they purchase specifically address the problem they are trying to solve,” said Craig Timothy, Director of Business Development at Traffic Logix.
Traffic Logix solutions have been installed in hundreds of locations throughout North America. Cities who use the products find that they are effective in reducing speed and offer several distinct advantages. The design of the products allows for simple installation that does not necessitate any road closures. In addition, this allows products to be moved when necessary either for placement on different streets or to avoid damage from snow plows. Customers report that the interlocking design of the products keep them firmly in place while other rubber products they have used have shifted. In addition to providing superior products, Traffic Logix customers have commended the company on the unusual level of customer service they offer throughout the purchasing and installation process.
“Our goal is to help cities obtain the solutions they need to slow traffic on their streets and keep people safe,” said Timothy. “That is what our company is about.”
